With the development of display technology, people request more and more display quality for display device. Quantum dots (refer to as QDs hereinafter) is spherical or spheroidal assemblies of semiconductor nanoparticles composed of II-VI group elements or III-V group elements, and particle diameter is generally between a few nanometers to tens of nanometers. The quantum confinement effect is occurred when the size of the particle of quantum dots are smaller or closed to the Exciton Bohr Radius of corresponding low-dimension materials, and the energy level of quasi-continuous of low-dimension materials turns into discrete structure of quantum dots materials to cause that QDs shows the property of special light amplification by stimulated emission of radiation. With the decreasing size of quantum dots and the increasing of band gap energy level, the energy that corresponding quantum dots need for exciting and the energy that quantum dots backs to ground state after excitation increases correspondingly and shows the excitation of quantum dots and blue shift of fluorescence spectroscopy; moreover, through controlling the size of quantum dots, photoluminescence spectroscopy may cover the entire visible spectrum. For example, the size of CdSe reduces to 2.0 nm from 6.6 nm, and the emission wavelength moves to 460 nm of blue spectrum from 635 nm of red spectrum by blue shift.
Advantages of quantum dots materials are centralized emission spectrum, high color purity and easy adjust light color through the size, structure or composition of quantum dots materials, and are used to effectively improve color gamut and color reproduction. Nowadays, it has been reported in many papers and patents that quantum dots are applied in Thin Film Transistor Liquid Crystal Display (TFT-LCD) area, wherein quantum dots substituted for color film materials gets people's attention. Using quantum dots to replace the traditional color resist may improve a great quantity of color gamut and penetration of TFT-LCD and have better display efficiency.
However, photoresist is made of composite resin resist quantum dots and then used to make quantum dots color film with following several problems: firstly, quantum dots has bad heat tolerance, and traditional TFT photolithography process goes through a temperature of over 200 degree. In order to make quantum dots photoresist be possible, the baked temperature of quantum dots photoresist must be decreased so that the ingredient of quantum dots photoresist should be a huge difference with traditional photoresist, and require a lot of research and development costs. Secondly, quantum dots are experience and toxic for most part, and large quantities of quantum dots are cleaned during photolithography process to cause waste and environment pollution. Once again, costly photolithography process may be used two or three times by using quantum dots photoresist.
COA (Color Filter on Array) is a technology that color layers are manufactured on the array substrate to form color filters. Alignment problem between color film substrate and array substrate is not existed in COA structure of display panel so that the difficulty of celling manufacturing process may decrease to avoid the error of alignment; hence, black array may be designed for narrow linewidth to improve aperture ratio.
PEDOT (poly-3,4-ethylene dioxythiophene) and PProDOT (poly-3,4-propylene dioxythiophene) are 3,4-substituted polythiophenes, and are a class of conductive polymer material having high electrical conductivity, and being stable and transparent under oxidation state. When graphene is mixed, graphene nanosheet having high conductivity and excellent mechanical properties may be used to improve conductivity, weatherability and hardness of PEDOT transparent conductive film. Besides, graphene nanosheet solution may well mix with PEDOT solution, may be used to form films by ordinary solution coating method and has actual prospects for industrial applications. Raw materials of graphene/PEDOT transparent conductive film are wide variety of sources, are simple manufacturing processes, are excellent performance, and may effectively replace ITO of which indium source is gradually lack; moreover, it reduces the use of PVD, decreases cost of production, and has huge marketing and prospects in flexible device.